Known locking mechanisms for aircraft doors exhibit a T-shaped handle, which can be moved from a locked position to an unlocked position by rotating it around a pivoting axis. Typical rotational angles measure 65 degrees.
These T-shaped handles are secured to many doors inside of aircraft. For example, the car door (cage door) of the so-called trolley lift conveyance system of the A 380 and A 340-600 exhibits such a handle. The so-called “trunk door” (outside door) is directly adjacent thereto.
If the T-shaped handle is in the open position, meaning folded up, the trunk door is not allowed to close, since the handle prevents this from happening.
The handle position is monitored optically or in part even mechanically, since the trunk door cannot be closed with the handle in the unlocked position. Another spacer located on the inside of the trunk door enhances this mechanical protection, preventing the outside door (trunk door) from closing when the inside door (cage door) is open.
However, damage may in this case be done to the door if excessive forces are applied, and the T-shaped handle presses too hard against the outside door, thereby defeating the mechanical protection.
EP 1 907 654 A2 and U.S. 2008/0210823 A1 show controllers for locking and unlocking aircraft doors, which exhibit several mechanical elements.